Oil bath air cleaner



Dec. 23, 1952 J. L. DEFFENBAUGH OIL BATH AIR CLEANER Filed Jan. 17, 1951 JL L IN VEN TOR.

Patented Dec. 23, 1952 UNITED STATES PATENT OFFICE.)

OIL BATH AIR CLEANER tion of California Application January 17, 1951,-Serial No. 206,449

3 Claims. 1

Thepresentinvention relates to an oil bath air cleanerfor an internal combustion engine or the like andmore particularly to means for preventing oil carry-over from the air cleaner into the engine.

In an oil'bath air cleaner of the type in which the'air is mixed with oil and passed through a set of relatively-fine mesh pre-cleaning screens before passing through a set of relatively coarse mesh screens for collecting the oil and dirt, one of the prin'cipal'difficulties encountered is that under some conditions the pre-cleaning screens become'plugged and the resulting high velocity air escaping around these screens carries a large part of the oil and dirt past the collecting screens intothe engine cylinders. This oil carry-over is undesirable in that the dirt formerly in the air is suspended in the oil and when it is carried into the engine cylinders causes rapid wear of the piston rings and cylinder walls. In addition, th oil carry-over frequently is the cause of the engine running away because the lubricating oil acts as fuel in the cylinders.

It is, therefore, an object of the present invention to overcome this difiiculty by providing an improved pre-cleaning screen for use in such an air cleaner to eliminate complete plugging of the screen, thus preventing the condition which causes o'il carry-over to the engine.

Other objects and advantages of this invention willbe'm'ade apparent in the following specification' wherein reference is made to the accompanying drawings.

In the drawings:

Fig. 1 is a view in side levation of an oil bath air cleaner embodying the present invention with parts broken away to more clearly illustrate its construction; and

Fig. 2 is a plan view of the improved precleaning screens with parts broken away to more clearly illustrate their construction.

In Fig. 1, an oil bath air cleaner embodying the present invention is illustrated as comprising a housing It] enclosing a set of relatively coarse mesh screens supported in frames shown at H and a set of relatively fine mesh pre-cleaning screens l2 interposed between the housing and a central inlet pipe I 3. The lower end of the housing is closed by a cup-like cover [4 detachably secured to the housing by bolts l6 and wing nuts ll. Adjacent its upper end, the housing is provided with an outlet l8 having a flanged end it for connection with the intake manifold of an internal combustion engine (not shown).

The screens H are held in place by a flanged 2. retainer ring 26 secured to the housing as by welding or the like. Th ring 20 also servesto position theset of pre-cleaning screens l2 which are disposed between upper and lower frame members 2| and 22 secured to each other by'cap screws 23; The lower framemember 22 is provided with inwardly extending ears 24- having slots illustrated at 25 in Fig. 2 for the reception of studs 26 secured to and extending from the inlet pipe 13. Wing nuts, only one of which is illustrated at 21 in Fig. 1, are provided for pressing the upper frame 2| into engagement with the retainer ring 20. Thus the pre-cleaning screen unit may be removed without disturbing the screens II. To remove the unit the" cover M is first removed then the wing nuts 21 are taken off to permit the pre-cleaning unit including the screens I2 and frame members 2| and 22 to dropfree' of the housing. The screens I2 may be separated from each other to facilitate cleaning them by removing the screws 23 from the unit. A centrally located inner cup-28 is-rigidly secured to the cover [4 in the path of the air discharged from the inletpipe. The cup 28 and cover I4 are adapted tocontain oil for intermixing with the air and communicate with each other by way of an opening 29 provided in the cup. Splashing of theoil is reduced by a funnel shaped splash shield 3| carried by framemember 22.

In operation, air entering the cleaner through inlet pipe l3 passes downwardly through cup 28 intermixing with the oil and then passes upwardly through the pre-cleaning screens I2 and screens II to the outlet l8. The removal of dirt from the air is primarily accomplished by contact with the oil, and it is imperative that good intermixing of the oil and air be obtained. In actual practice, the cup 28 is practically swept free of oil which is collected on the screens and is fed back into the entering air stream by way of the opening 29 in the cup 28 as well as over its upper edge. After the air passes through the cup, a substantial portion of the oil and dirt is collected on the pre-cleaning screens 12 and is blown outwardly toward the splash shield 3| where it is returned to the cup-like cover M by gravity. This oil carries a majority of the dirt formerly in the air which is permitted to settle out in the cover, and relatively clean oil is then fed. back into the inner cup for recirculation through the cleaner. That part of the oil which is carried through the screens [2 is collected on the screens H and flows downwardly by gravity along the outside wall of the housing across screens I2 and then downwardly through an annular space 32 between the inlet pipe I3 and the frames supporting the screens. This 011 is relatively clean and is fed back into the entering air stream for recirculation through the cleaner.

In the past, one of the principal difficulties encountered with this type of cleaner was that operation in excessively dirty air for prolonged periods resulted in the screens I2 becoming plugged. As a result, all of the air going to the engine was forced to pass upwardly through annular space 32 at a high velocity. This passage of high velocity air caused channeling through the screens I I and carried substantial quantities of oil through the outlet I8 into the engine cylinders. The passage of air through annular space 32 at a high velocity prevented the return of oil collected on the screens II further aggravating the condition, as well as causing the oil to become laden with abrasives which, in turn, caused rapid wear of the piston rings and cylinder walls.

This difiiculty has been overcome in the present invention by the provision of a plurality of spaced openings 33 provided in the screens I2. Guide pins 34 carried in the lower frame member 22 facilitate alignment of the openings of the several screens at assembly. These openings are of such a size and are so spaced that during normal operation, only a small part of the air passes through the openings, and as a result there is a minimum of change in the air cleaning efficiency. However, in the event that the screens become plugged, the openings 33 allow air to pass through the pro-cleaning screens at a velocity below which channeling in the screens I I occurs thus avoiding the condition which causes oil carry-over to the engine.

A further improvement includes the provision of a plurality of openings 35 adjacent the upper end of the splash shield 3I which permits the oil collected on the screens I2 to return to the cover H along the outside of the splash shield well out of the entering air stream. These openings are provided to avoid the possibility of dirt laden oil recirculating within the cleaner without allowing a settling out period for the dirt.

I claim:

1. In an oil bath air cleaner comprising a housing containing oil for intermixing with the incoming air, a set of relatively fine mesh screens for pre-cleaning the mixture of air and oil, and a set of relatively coarse mesh screens for collecting the oil carried through the pre-cleaning screens, said pro-cleaning screens having relatively large perforations to prohibit complete stoppage of air flow through the screens by foreign matter collected thereon and means for removing the precleaning screens from the housing without removing the coarse mesh screens.

2. In an oil bath air cleaner comprising a housing containing oil for intermixing with the incoming air, a set of relatively fine mesh screens for pre-cleaning the mixture of air and oil, a set of relatively coarse mesh screens for collecting the oil carried through the pre-cleaning screens, relatively large perforations through said pre-cleaning screens to prohibit complete stoppage of air flow through the screens by foreign matter collected thereon, separable frame members for clamping the pre-cleaning screens together, and guide pins extending from one of the frame members for aligning the perforations in the screens one of said separable frame members having perforate lugs thereon and threaded securing means in the housing passing through said lugs to permit removal of the frame members and pre-cleaning screens.

3. In an oil bath air cleaner comprising a housing having a reservoir adapted to contain oil for intermixing with the incoming air, a set of relatively fine mesh screens for pre-cleaning the mixture of air and oil, a set of relatively coarse mesh screens for collecting the oil carried through the pre-cleaning screens, separable frame members for clamping the pre-cleaning screens together, a funnel shaped splash shield supported by and below the frame members, and perforations adjacent the upper part of the splash shield to allow oil collected on the pro-cleaning screens to return to said reservoir along the outside surface of the splash shield.

JOHN L. DEFFENBAUGH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

